Preparation And Application Of Fluororubber Composites

In this paper,fluororubber foaming materials were prepared by supercritical foaming.The effects of different degree of pre-crosslinking,different carbon black contents and secondary cross-linking on the rheological behavior and foaming behavior of fluororubber were studied.Sol-gel method was used to prepared of low-density fluororubber aerogels,and effects of graphene content on the microstructure,heat resistance,compression properties and thermal conductivity of fluororubber aerogels were studied.By using fluororubbers with carbon nanotubes or carbon black in solvents,the fluororubber/carbon nanotube superhydrophobic coating and fluororubber/carbon black@PU sponge were prepared.The microstructure,hydrophobicity and wear resistance of fluororubber/carbon nanotube superhydrophobic coating and microstructure,hydrophobicity and oil-water separation ability of fluororubber /carbon black @PU spong were studied.The fluororubber foaming materials were prepared by pre-crosslinking and then supercritical foaming.The effects of different degree of pre-crosslinking,different carbon black contents and secondary cross-linking on the rheological behavior and foaming behavior of fluororubber were studied.The results showed that with the increase of pre-crosslinking degree,the slope of the stress-strain curve of the fluororubber showd a significant upward trend,and the strain at the fracture point of specimen(the elongation at break)gradually decreased.With the increase of precrosslinking degree,the complex viscosity,viscous modulus and elastic modulus of the fluororubber were increasd,and the loss factor was decreased.The cell size and the cell uniformity of the foamed materials were gradually decreased ether.After secondary cross-linking,the cells were more full and uniform when the pre-crosslinking is low-degree,and some large holes and string holes occured when the pre-crosslinking is mid-degree and high-degree.The materials without secondary cross-linking,with the increased of time,the density of the material gradually increased.After secondary crosslinking in a oven at 170 ° C,the density remained constant,and at the same time,it had a good thermal stability at high temperature(220 ° C).With the increased of carbon black content,the modulus of the composites increased before 800% strain,then the modulus decreased gradually.The macroporous structure of the foamed materials gradually decreased and the cell size was more uniform.The cell of fluororubber composites foaming materials which were not secondary cross-linking were slightly slack,and the cell structure was more rounded,and the density of the sample gradually increased as the time went by.After the secondary cross-linking,the cells of the foamed materials were more fuller,and the sample density remained stable.The fluororubber aerogels were prepared by sol-gel method and the effects of graphene content on the microstructure,heat resistance,compression properties and thermal conductivity of fluororubber aerogels were investigated.The results showed that with the increase of graphene content,the cell size was gradually reduced and the fluororubber aerogel was closed-cell.In the fluororubber aerogel matrix,the graphene was mainly filled as a reinforcing agent and the fluororubber aerogel has excellent flexibility and extremely low density,and can be folded or twisted.The fluororubber wet gel had good effect and good strength and compressibility.The aerogel prepared after foaming was smooth and uniform from the surface,and the regularity between the cells was good.With the increased of graphene content,the compression curves showed an upward trend,and the compression modulus gradually increased.As the graphene content increased,the thermal conductivity of the fluororubber aerogels gradually increased,reaching a minimum of 0.02 W/m·K.The fluororubber/carbon nanotube superhydrophobic coating and the fluororubber/carbon black@PU sponge were prepared by combining the fluororubber with carbon nanotubes and carbon black in a solvent respectively.,the microstructure,hydrophobicity,wear resistance of fluororubber/carbon nanotube superhydrophobic coating and the microstructure,hydrophobicity and oil-water separation ability of the fluororubber/carbon black @PU sponge were studied.The results showed that when the mass ratio of fluororubber to carbon nanotube was 5:1,the surface structure of the prepared coating was more stable and hydrophobic,and the fluororubber/carbon nanotube@PET fabric had better wear resistance.After some times of friction,it could maintain good hydrophobicity.When the ratio of fluororubber/carbon black was 8:4,the prepared superhydrophobic sponge was better in hydrophobicity and more stable.The fluororubber/carbon black@PU superhydrophobic sponge had good hydrophobicity after released by repeated compression,it still had good hydrophobic effect when compressed in air or water,and its crosslinking degree was also high.The fluororubber/carbon black@PU sponge has better oil-water separation ability and repeated oil absorption capacity,the absorption capacity of a variety of solvents and oils can reach 20-50 times on its own weight.